1. Field of the Invention
The invention relates to a method and devices for controlling the combustion of an internal combustion engine functioning according to a four-stroke cycle with spark or other ignition, with valve timing or equipped with a rotary intake and/or exhaust distributor.
2. Description of Background and Relevant Information
The thermodynamic efficiency of the combustion of internal combustion engines is directly proportional to the gas pressure at the end of the compression stroke and consequently to the load of the engine, itself a function of the opening of the accelerator valve. The specific consumption of the engine is related to the thermodynamic efficiency, which amounts to saying that for a given engine displacement the less torque and/or power required the more the specific consumption increases. This is extremely penalizing especially when the engine equips an automobile because the result is that at low speeds and low loads the fuel consumption is very substantial, and consequently so are the polluting exhaust emissions, but, especially in the city, the engine is always used at a low speed and at low loads. To clarify, an automobile engine that consumes at average or full load, approximately 200 to 250 grams of fuel per horsepower and per hour on the highway sees its consumption in the city increased to approximately 1000 or even 2000 grams of fuel per horsepower and per hour.
Conscious of this problem, motorists sought to improve the consumption at low loads in various manners: either by producing engines with poor or very poor mixtures (in the case of stratified load engines); or by trying to obtain variable compression ratio engines in order to try to increase the pressure at the end of compression; or even by "disengaging" one or more cylinders in order to increase the load on the cylinders that remain in operation, for equivalent power.
The solutions have the disadvantage of only very partially resolving the problem and are in addition in certain cases particularly difficult and onerous to implement.